Coaxial counter-rotating rotor system

Abstract

A system and method to tilt coaxial counter-rotating rotor hub assemblies relative to a fuselage. The system includes a first rotor hub assembly and a second rotor hub assembly spaced apart from the first hub assembly and carried by the fuselage. The method includes pivotally attaching the first rotor hub assembly and the second rotor hub assembly to a pivot joint and thereafter tilting the first rotor hub assembly and the second rotor hub assembly about the pivot joint with a driver.

What is claimed is: 
     
       1. A helicopter, comprising:
 a fuselage; 
 an engine disposed within the fuselage; 
 a transmission rotatably coupled to the engine and pivotally attached to the fuselage; and 
 a rotor system carried by the fuselage, the rotor system having:
 a first rotor hub assembly; 
 a second rotor hub assembly spaced apart from the first hub assembly; 
 a plurality of rotor blades coupled to both the first hub assembly and the second hub assembly; 
 a rotor mast, having:
 a first section rotatably engaged to the transmission; and 
 a second section attached to both the first rotor hub assembly and the second rotor hub assembly; and 
 
 a driver operably associated with the rotor mast; and 
 
 a pivot joint pivotally attached between the transmission and the rotor system; 
 wherein, during flight, the engine rotates the rotor system via the transmission, while the driver pivots the second section of the rotor mast, which in turn tilts the first rotor hub assembly and the second rotor hub assembly about the pivot joint relative to the fuselage. 
 
     
     
       2. The helicopter of  claim 1 , further comprising:
 a control system operably associated with the driver; 
 wherein the control system commands the driver to pivot the second section of the rotor mast. 
 
     
     
       3. The helicopter of  claim 2 , wherein the control system autonomously commands the driver to pivot the second section of the rotor mast. 
     
     
       4. The helicopter of  claim 2 , further comprising:
 a controller operably associated with the control system; 
 wherein the controller is manually manipulated, which in turn pivots the second section of the rotor mast. 
 
     
     
       5. The helicopter of  claim 1 , wherein the first rotor hub assembly and the second rotor hub assembly are coaxially aligned. 
     
     
       6. The helicopter of  claim 1 , wherein the driver is a hydraulic system.